First year St. Gaudens Element Conc. (%) 1 Al 0.03 2 Si 0.15 3 S 0.05 4 Cl 0.04 5 Ca 0.05 6 Fe 0.03 7 Ni 0.03 8 Cu 9.89 9 Ag 0.11 10 Hf 0.10 11 Au 89.52 https://moneditis.com/2017/03/31/20-us-dollars-saint-gaudens-1907-double-eagle-xrf/